# std::chrono::duration<Rep,Period>::operator+=, -=, *=, /=, %=

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< cpp‎ | chrono‎ | duration

| (1) |
duration& operator+=( const duration& d ); |  | (since C++11) (constexpr since C++17)
| (2) |
duration& operator-=( const duration& d ); |  | (since C++11) (constexpr since C++17)
| (3) |
duration& operator*=( const rep& rhs ); |  | (since C++11) (constexpr since C++17)
| (4) |
duration& operator/=( const rep& rhs ); |  | (since C++11) (constexpr since C++17)
| (5) |
duration& operator%=( const rep& rhs ); |  | (since C++11) (constexpr since C++17)
| (6) |
duration& operator%=( const duration& rhs ); |  | (since C++11) (constexpr since C++17)

Performs compound assignments between two durations with the same period or between a duration and a tick count value.

If `rep_` is the member variable holding the number of ticks in this duration object,

1) Equivalent to rep_ += d.count(); return *this;.
2) Equivalent to rep_ -= d.count(); return *this;.
3) Equivalent to rep_ *= rhs; return *this;.
4) Equivalent to rep_ /= rhs; return *this;.
5) Equivalent to rep_ %= rhs; return *this;.
6) Equivalent to rep_ %= d.count(); return *this;.

### Parameters

d | - | duration on the right-hand side of the operator
rhs | - | number of ticks on the right-hand side of the operator

### Return value

A reference to this duration after modification.

### Example

Run this code

    #include <chrono>
    #include <iostream>

    int main()
    {
        std::chrono::minutes m(11);
        m *= 2;
        m += std::chrono::hours(10); // hours implicitly convert to minutes
        std::cout << m.count() << " minutes equals "
                  << std::chrono::duration_cast<std::chrono::hours>(m).count()
                  << " hours and ";
        m %= std::chrono::hours(1);
        std::cout << m.count() << " minutes\n";
    }

Output:

    622 minutes equals 10 hours and 22 minutes

### See also

operator++operator++(int)operator--operator--(int) | increments or decrements the tick count (public member function)
operator+operator-operator*operator/operator% (C++11) | implements arithmetic operations with durations as arguments (function template)

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